PB-18 Probiotic for Mild to Moderate Depression

NCT07562516 | Not Yet Recruiting

• 1 other identifier: IIT20260039C-R1
• Study Type: interventional
• Target: 88
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this clinical trial is to learn if Bifidobacterium PB-18 can treat mild to moderate depressive disorder in adults aged 18 to 65 years who are not taking antidepressants or other psychotropic medications during the study. It will also learn about the safety of Bifidobacterium PB-18 and explore its potential effects on the gut-brain axis. The main questions it aims to answer are: Does Bifidobacterium PB-18 increase the response rate at Week 8, defined as a reduction of at least 50% from baseline in the 17-item Hamilton Depression Rating Scale (HAMD-17)? What adverse events occur in participants receiving Bifidobacterium PB-18? How do gut microbiota, metabolite profiles, and related biological markers change after treatment with Bifidobacterium PB-18? Researchers will compare Bifidobacterium PB-18 with a placebo, a look-alike powder that does not contain PB-18, to see if Bifidobacterium PB-18 improves depressive symptoms. Participants will: Be randomly assigned to receive Bifidobacterium PB-18 or placebo in a 1:1 ratio Take the assigned study product once daily for 8 weeks Visit the study site at baseline, Week 4, and Week 8 for symptom and safety assessments Complete study questionnaires, including HAMD-17, HAMA, PSQI, and CBCT Provide blood and stool samples at baseline and Week 8 for exploratory biological analyses

Conditions

Depressive Disorder

Keywords

Bifidobacterium PB-18; Probiotic; Depression; Gut-Brain Axis; Placebo-Controlled; Randomized; Double-Blind

Outcome Measures

Primary Outcomes (1)

• Response Rate at Week 8 Based on the 17-Item Hamilton Depression Rating Scale

  Between-group difference in response rate at Week 8. Response is defined as a reduction of at least 50 percent from baseline in the total score on the 17-Item Hamilton Depression Rating Scale.

  Week 8

Secondary Outcomes (7)

• Remission Rate at Week 8 Based on the 17-Item Hamilton Depression Rating Scale

  Week 8

• Response Rate at Week 4 Based on the 17-Item Hamilton Depression Rating Scale

  Week 4

• Remission Rate at Week 4 Based on the 17-Item Hamilton Depression Rating Scale

  Week 4

• Change From Baseline in Total Score on the 17-Item Hamilton Depression Rating Scale

  Baseline, Week 4, and Week 8

• Change From Baseline in Total Score on the Hamilton Anxiety Rating Scale

  Baseline, Week 4, and Week 8

Study Arms (2)

Bifidobacterium PB-18

EXPERIMENTAL

Participants receive Bifidobacterium PB-18 powder orally once daily for 8 weeks. Each daily dose contains 1 × 10\^10 CFU of PB-18.

Dietary Supplement: Bifidobacterium

Placebo

PLACEBO COMPARATOR

Participants receive a matching placebo powder orally once daily for 8 weeks. The placebo is maltodextrin and matches the active product in appearance, color, smell, taste, packaging, and administration schedule, but does not contain PB-18.

Other: Placebo

Interventions

Bifidobacterium DIETARY_SUPPLEMENT

Participants receive Bifidobacterium PB-18 powder orally once daily for 8 weeks. Each daily dose contains 1 × 10\^10 CFU of PB-18. The study product is administered from baseline through Week 8.

Also known as: Bifidobacterium PB-18, Bifidobacterium longum subsp. infantis

Bifidobacterium PB-18

Placebo OTHER

Participants receive a matching placebo powder orally once daily for 8 weeks. The placebo is maltodextrin and matches the PB-18 product in dose schedule, appearance, color, smell, taste, packaging, and administration, but does not contain PB-18.

Also known as: Maltodextrin placebo, Matching placebo

Placebo

Eligibility Criteria

• Age: 16 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Outpatient or inpatient participants, aged 18 to 65 years (inclusive), of any sex
• Current episode meets Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria for depressive disorder
• Baseline score on the 17-Item Hamilton Depression Rating Scale is 7 to 24, inclusive
• No concomitant use of antidepressants or other psychotropic medications during the study
• Elementary school education or above, able to understand the study requirements and complete the rating scales
• Participant personally signs the informed consent form and is willing to complete follow-up according to the study protocol

You may not qualify if:

• Current or past diagnosis, according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria, of bipolar disorder, schizophrenia spectrum and other psychotic disorders, neurocognitive disorders, neurodevelopmental disorders, or substance-related and addictive disorders
• Presence of significant psychotic symptoms, such as delusions or hallucinations
• Severe or unstable diseases of the central nervous system, cardiovascular system, respiratory system, liver, kidneys, endocrine system, hematologic system, or other systems that, in the investigator's judgment, make the participant unsuitable for the study
• Evident suicide risk, defined as a score of 1 or higher on the suicide item of the 17-Item Hamilton Depression Rating Scale
• Active inflammatory disease
• Gastrointestinal infection, tumor, or other organic digestive disease, including but not limited to irritable bowel syndrome, Crohn disease, ulcerative colitis, or celiac disease
• History of major gastrointestinal surgery
• Use of antibiotics, probiotics, prebiotics, or related functional products within 1 month before study entry
• Allergy to the study product or any of its components
• Pregnant or breastfeeding women
• Unable or unwilling to take the study product as required by the protocol
• Any other condition that, in the investigator's judgment, makes the participant unsuitable for the study

Sponsors & Collaborators

• First Affiliated Hospital of Zhejiang University: lead

MeSH Terms

Conditions

Depressive Disorder; Depression

Condition Hierarchy (Ancestors)

Mood Disorders; Mental Disorders; Behavioral Symptoms; Behavior

Study Officials

• Jing Lu, PhD

  Zhejiang University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jing Lu, PhD

CONTACT

15858200010; Lujing2016@zju.edu.cn

Wenhao Chen, MD

CONTACT

19857175751; chenwenhao@zju.edu.cn

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Participants, investigators, and outcome assessors are blinded to treatment assignment. Study product allocation, coding, and dispensing are managed by independent personnel. The placebo matches the active product in appearance, color, smell, taste, packaging, and administration schedule. Emergency unblinding is permitted only when necessary for participant safety.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Participants are randomly assigned in a 1:1 ratio to 1 of 2 parallel groups to receive either Bifidobacterium PB-18 or matching placebo for 8 weeks. The placebo matches the active product in appearance, color, smell, taste, and administration schedule. Participants, investigators, and outcome assessors remain blinded throughout the study unless emergency unblinding is required.

Study Record Dates

• First Submitted: April 26, 2026
• First Posted: May 1, 2026
• Study Start: May 5, 2026
• Primary Completion (Estimated): January 31, 2027
• Study Completion (Estimated): April 30, 2027
• Last Updated: May 1, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share